|||||||||||||III USOO5302790A United States Patent 19 (11) Patent Number: 5,302,790 Turpin (45) Date of Patent: Apr. 12, 1994

54) MICROWAVE POPCORN POPPING BAG 4,904,488 2/1990 La Baw et al...... 426/ 4,948,932 8/1990 Clough ...... 219/10.55 (75) Inventor: Charles H. Turpin, Minneapolis, 4,973,810 1 1/1990 Brauner ...... 219/10.55 E Minn. 4,982,064 1/1991 Hartman et al. . ... 219/10.55 E (73) Assignee:w Golden Valley Microwave Foods Inc., 5,044,7775,011,299 4/19919/1991 WatkinsBlack, Jr. et et al. al...... 383/26383/100 Edina, Minn. 5,081,330 1/1992 Brandberg et al...... 219/10.55 E 21 Appl. No.: 1 5,097,107 3/1992 Watkins et al...... 219/10.55 E A. o.: 959,68 5,153,402 10/1992 Quick et al...... 219/10.55 E 22 Filed: Oct. 13, 1992 Primary Examiner-Bruce A. Reynolds Assistant Examiner-Tu Hoang (63) Related U.S. Application Data Attorney, Agent, or Firm-James V. Harmon Continuation-in-part of Ser. No. 852,291, Mar. 16, 1992, abandoned. 57 ABSTRACT 51) Int. Cl'...... Hose 6/so For popping popcorn in a microwave oven, a flexible 52) U.S.OMO Clat 08 we d8 due e o wo. 4 P 4 we w or now ow 219/727y 219/730; bag is provided which contains popcorn and includes a 219/732; 426/107; 426/113; 426/234; 426/243; collapsible stand. The bag has upper and lower oppos 99/DIG. 14; 383/100; 383/126; 53/434 ing face panels connected together by longitudinally 58 Field of search...... 219/10.55 E, 10.55 F, extending centrally projecting gussets that are integral 219/10.55 M, 10.55 D; 426/107, 110, 113, 124, with the face panels. Prior to popping, the gussets are 234,243,99/DIG. 14.383/100,126, 104 folded between the upper and lower face panels of the 53/434, 449 bag. The panels and gussets are preferably formed from (56) Ref Cited a pair of superimposed sheets of paper that are lami eferences Cite nated together with adhesive. Popcorn is placed in the U.S. PATENT DOCUMENTS bag and the bag ends are sealed. A microwave heating 1,944,089 1/1934 Litchfield ...... 158/9 susceptor of any suitable type is provided in the lower 3,357,152 12/1967 Geigel ...... 53/29 panel of the bag or elsewhere in the bag if desired. 3,381,574 12/1974 Katz et al...... 426/107 During popping of the popcorn kernels, the bag in 3,973,045 8/1976 Brandberg et al...... 426/O creases in size and the gussets expand outwardly as the 4,038,425 7/1977 Brandberg et al...... 426/07 bag becomes filled with popped kernels, hot vapor and 4,219,573 8/1980 Borek ...... 426/107 steam. To ensure that microwave energy will transfer 4,355,757 10/1982 Roccaforte ...... 229/33 well to the popcorn so that the popcorn pops efficiently, 4,450,180 5/1984 Watkins ...... 426/107 4,453,665 6/1984 Roccaforte et al...... 229/4 B popping can be conducted with the stand folded flat, 4,477,705 10/1984 Danley et al...... 21.9/10.55 E i.e., collapsed in certain ovens or, if desired, popping 4,584,202 4/1986 Roccaforte ...... 426/11 can be carried out with the stand erected so as to elevate 4,586,649 5/1986 Webinger ...... 426/111 the lower panel of the bag about 2 cm from the support 4,698,472 10/1987 Cox et al...... 29/10.55 E ing surface of the microwave oven. 4,727,706 3/1988 Beer ...... 53/434 4,735,513 4/1988 Watkins et al...... 383/116 7 Claims, 3 Drawing Sheets

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U.S. Patent Apr. 12, 1994 Sheet 1 of 3 5,302,790

U.S. Patent Apr. 12, 1994 Sheet 2 of 3 5,302,790

FIG.4

FIG.5 U.S. Patent Apr. 12, 1994 Sheet 3 of 3 5,302,790

F.G. 6 17b 7

F.G. 6A

5,302,790 2 A major objective of the present invention is to pro MICROWAVE POPCORN POPPING BAG vide an improved microwave popcorn popping bag in which energy can be transmitted efficiently to the sus This is a continuation-in-part of prior application Ser. ceptor in both of the above types of ovens. A more No. 07/852,291, filed Mar. 16, 1992, entitled SPACE specific objective is to find a way of mass producing an EFFICIENT MICROWAVE POPCORN POPPING inexpensive disposable paper bag that can be placed BAG AND METHOD, selectively in either of two or more positions within the microwave oven to assure popping at maximum effi FIELD OF THE INVENTION ciency. Another more specific object is to provide an This invention relates to a microwave corn popping 10 inexpensive popcorn bag that can be mass produced bag. efficiently and in which cooking can be carried out in BACKGROUND OF THE INVENTION either a raised or a lowered position. These and other more detailed and specific objects of At the time microwave popcorn was first commer the invention will be better understood by reference to cialized, microwave popcorn bags were sized to be the 15 the following detailed description and figures which largest size that would fit in the most commonly avail illustrate by way of example but a few of the various able ovens in use at the time. A de facto standard size of about 100 grams resulted. This size has come to be forms of the invention within the scope of the appended preferred by microwave popcorn customers, with sizes claims. larger, and especially smaller, being much less accept 20 SUMMARY OF THE INVENTION able as shown by relative sales volume. Briefly, for the purpose of popping popcorn in a This size fits and works well in most of today's micro microwave oven, the present invention provides a flexi wave ovens. However, there is one class of oven where ble bag containing popcorn and having a collapsible this size does not work well-and that is the class of stand as a part of the bag. The bag includes upper and oven wherein a turntable is used to enhance uniformity 25 of heating. In such ovens, if the 100 gram bag is too lower face panels defining the major faces of the bag. close to the maximum space capacity of the oven, the Connected to and extending between the faces of the bag can catch or hang up and so no longer rotate, thus bag are left and right longitudinally extending, centrally inactivating the uniformity of heating feature of the projecting gussets that are integral with the face panels. oven turntable, resulting in reduced pop volume and 30 Prior to popping, the gussets are folded between the sometimes even scorching. Such small ovens may often upper and lower face panels of the bag. The panels and have a turntable of about 23 cm or less in diameter and gussets are preferably formed from a pair of superim are very common in some markets, making it unfeasible posed sheets of paper that are laminated together with to market the most popular bag size in those markets. In adhesive. Popcorn is placed in the bag and the bag ends fact, the largest de facto standard size that will fit these 35 are sealed. A microwave heating susceptor of any suit ovens is the 50 gram size, which uses a bag having a able type is provided in the lower panel of the bag. If height of only about 23 cm and a width of about 10 cm desired, the bag ends can be cut in an arcuate configura across each face. tion, either as a continuously curved convex arc or as Another problem in certain microwave ovens is that several straight adjoining cut segments. During pop the area of maximum field intensity is in an unusual ping of the popcorn kernels, the bag increases in size position owing to the design of the oven cavity or the and as this happens, gussets expand outwardly as the presence of a metal cooking surface. For example, in a bag becomes filled with popped kernels, hot vapor and typical Japanese oven it has been found that the maxi Steam. mum field intensity is not located at or immediately To ensure that microwave energy will couple well above the support surface within the oven as it is in 45 with the popcorn so that the popcorn pops efficiently, typical U.S. ovens. Japanese ovens are characterized by the bag has a stand capable of collapsing by being the presence of a metal cooking surface, i.e., a metal folded flat for shipment and storage. When erected, the support surface such as a turntable for the food at the stand elevates the lower panel of the bag about 2 cm bottom of the oven compartment. Foods like popcorn from the supporting surface within the microwave oven which depend on an electric field powered susceptor in SO cooking chamber. the bottom of a paper container, e.g., a bag, are not heated very well in ovens of this kind. As a result, the THE FIGURES popcorn pops slowly, and very often popping is incom FIG. 1 is a perspective view of a microwave oven plete, resulting in a large number of unpopped kernels holding a bag in accordance with the invention as it which consumers find unacceptable. In addition, heat 55 appears just after popping; ing may be spotty, causing popcorn in some parts of the FIG. 2 is an enlarged perspective view of the turnta bag to burn or kernels in other portions of the package ble and popcorn bag illustrated in FIG. 1 as it appears remain unpopped. This is a particularly serious problem after it has been fully inflated and the corn has been to the consumer who often perceives the packaged popped; popcorn as a poor product and may never buy it again. FIG. 3 is a perspective view of the package in a col By contrast, other ovens such as those commonly mar lapsed condition as it appears prior to popping of the keted in the United States exhibit a maximum micro corn; wave field intensity that is positioned very close to the FIG. 4 is a top view of the package of FIG. 2 after cooking surface (the oven floor), e.g., about one-six popping; teenth to about one-eighth inch above the cooking sur 65 FIG. 5 is a side view of the package after popping; face so that the microwave energy is transmitted very FIG. 6 is a perspective view of the collapsible stand efficiently to the susceptor of a packaged food product illustrated in FIGS. 4 and 5 as seen before it is bonded resting directly on the floor of the oven. to the lower surface of the bag; 5,302,790 3 4. FIG. 6A is a partial side elevational view of the bag straight segments 36, 21 and 38 joined end-to-end to with the stand in a partially collapsed position; form a convex arc. The panels and gussets are bonded FIG. 7 is a plan view of the lower surface of a pop together by means of an arcuate line of adhesive com corn popping bag having another form of collapsible posed of segments 40, 42 and 44 aligned with the cut stand; edges 38, 21 and 36, respectively. Similarly, the con FIG. 8 is a perspective view of one of the legs of the toured arcuate bottom cut end B of the bag can be a stand shown in FIG. 7; continuously curved arc as shown at 24, if desired, FIG. 8B is a perspective view of the leg of FIG. 8 rather than being formed of several connected straight folded to its erect position; and segments. The arcuate cut ends A and B of the bag 10 FIG. 9 is a partial vertical sectional view taken on 10 both have a convex shape with respect to the center of line 9-9 of FIG. 7 on an enlarged scale. the bag and can, if desired, form a convex arc such as a circular or elliptical arc about the center point C of the DETAILED DESCRIPTION OF THE bag 10. INVENTION By viewing FIG. 2, it will be seen that the adhesive Refer now to the figures. Shown in FIG. 1 is a micro 15 line 40 consists of a pair of adhesive bonds 40a and 40b wave oven 4 having the usual controls 5 and an oven between the gusset fold 18 in the upper and lower face cooking chamber 6 provided with a rotatable turntable panels 12 and 14. Similarly, the adhesive line 44 includes 7 upon which is placed a popcorn bag 10 embodying an upper segment 44a and a lower segment 44b which one alternative form of the invention. In FIGS. 1, 2, 4 bond the gusset 16 and the upper and lower face panels. and 5 the popcorn bag 10 is shown as it appears in the 20 The adhesive line 42 bonds the face panels 12 and 14 expanded condition during and immediately after pop between the gusset folds 16 and 18. ping. Refer now to FIG. 3 which illustrates clearly how The bag 10 is composed of flexible microwave trans the gussets are cut in the embodiment of FIGS. 1-5. It parent sheet material, preferably of a pair of paper plies will be seen that the height of each of the gussets 16 and 10a and 10b (FIG. 2) that are superimposed and sealed 25 18 is greatest near the center of the bag but diminishes together by means of adhesive, i.e., laminated to one proceeding laterally toward the side edges 23 and 25 of another to form a composite structure. The composition the bag 10. The gusset will thus have a generally trape of the bag 10, adhesives used, and its mode of assembly, zoidal configuration prior to popping when the bag is etc., can be as described in any of the following patents flat as in FIG. 3. Each end of each gusset 16, 18 is se which are incorporated herein by reference: U.S. Pat. 30 curely bonded to the adjacent face panels 12, 14 by Nos. 4,691,374; 4,735,513; 4,878,765; 4,450, 180; means of the lines of adhesive 26a, 26b, 30a, 30b, at the 5,044,777 or 5,081,330. top of the bag and 40a, 40b, 44a, 44b at the bottom of the The bag 10 includes a flat upper face panel 12 and a bag. flat lower face panel 14. The upper face panel 12 is Bonded as shown in FIGS. 4, 5 and 6A, e.g., by provided with a longitudinally extending, adhesively 35 means of adhesive, to the bottom of the bag 10 is a stand bonded seam 12a that bonds the edges of the cut sheet 17 formed, for example, from microwave transparent from which the bag is formed together along the length paperboard having a pair of upright segments 17a termi of the bag. Extending longitudinally of the bag 10 be nating in centrally folded tabs T which are bonded by tween the face panels 12, 14 are a pair of longitudinally being glued to the bottom panel 14 of the bag 10 for extending, centrally projecting folded gussets 16 and 18 supporting the bag at a height of, say, about 2 cm above which are integral with face panels 12 and 14. the turntable 7. It will be noted that the tabs T are rela Within the bag 10 is a charge 13 of popcorn, prefera tively small in size compared to the susceptor 14b. This bly together with a quantity of shortening. Bonded will help to avoid overheating of the susceptor 14b. The between the plies 10a, 10b beneath the charge 13 of stand 17 in this case includes a central rectangular bot popcorn and shortening is a susceptor 14b. While any 45 tom panel designated by the numeral 17c (FIGS. 5 and suitable type of susceptor known to the art can be em 6). Fold lines 17d, i.e., pre-formed creases in the paper ployed, the susceptor 14b preferably comprises a thin board, define the intersection between the tabs T, the sheet of plastic such as 0.5 mil polyethylene terephthal upright segments 17a and 17b, and the lower panel 17c. ate having a thin semiconductive coating of metal, e.g., The stand 17 is in this way collapsible so that it will aluminum, vacuum electrodeposited thereon for ab 50 function both in the collapsed position illustrated in sorbing microwave energy and converting it to heat. FIG. 6A or, by folding the adjoining panels along the The ends of the optional form of the bag 10 shown in fold line 17d to an erect position, in the erect position FIGS. 1-5 are cut in a particular way. Other embodi shown in FIG. 5. Accordingly, the stand 17 can be used ments to be described below have straight cut ends. As to position the bag 10 in at least two alternate positions shown in FIG. 3, the bag 10 is provided with a top end 55 at different elevations for different applications; namely, A and a bottom end B. The top end A is provided with by placing the stand 17 in an erect position (FIGS. 4-6) an arcuate cut edge which can, if desired, either be in or a collapsed position (FIG. 6A) to suit whatever con the form of a continuously curved convex arc 22 or, as ditions exist in the particular oven in which the popcorn shown in the figure, composed of several straight ad bag 10 is cooked. The stand 17 can thus be thought of as joining cut segments, in this case a straight center seg a collapsible stand suited for positioning the bag 10 at ment 20 and inclined cut segments 34 and 32 proceeding selected positions within the oven, namely, at two or outwardly and downwardly from the central center more elevations; one position (when the stand 17 is most segment 20. The top end A of the bag 10 is glued collapsed) locating the popcorn within the bag 10 very together by means of three adhesive strips 26, 28 and 30 close to the oven supporting surface and the second which are aligned with the cut edges 32, 20 and 34, position (when the stand 17 is erect) locating the bottom respectively. wall 17c of the bag 10 in a raised position in spaced Similarly, the bottom end B of the bag 10 is provided relationship with the oven supporting surface, e.g., the with an arcuately contoured cut end composed of three oven turntable 7, and in this way placing the popcorn as 5,302,790 5 6 well as the susceptor 14b where both will efficiently hancing energy transfer to the susceptor 52a when the absorb the microwave energy to pop the corn more oven floor or food support is composed of metal. completely and evenly. When the stand 17 is folded halfway or to any other intermediate position, it will Commercial Application and Results support the bag 10 at some intermediate position be 5 The present invention was employed for popping tween the raised and lowered position to suit any kind popcorn in four different kinds of microwave ovens. In of oven encountered. . . all of the tests, identical standard commercial produc The bottom seal B is made very strong to prevent it tion popcorn bags were employed of a type manufac from popping open due to internal pressure prior to the tured by the assignee, Golden Valley Microwave top seal A in any suitable manner. This can be accom 10 Foods, Inc., with a nominal capacity of 3.5 ounces. plished in any suitable way as by having the bottom seal Some of the bags had stands attached as described 42 extend further toward the top of the bag, thereby herein, and other control bags had no stand. intersecting the seals 40, 44 higher up so that the seals All of the bags were filled with 71 gms. of corn and become redundant. The seal at the top A of the bag is 29 gms. of shortening, salt and butter flavoring. The net preferably made somewhat weaker than the bottom seal 15 weight of all bags tested within --/- 1.5 gms. of the B to provide a normally closed steam vent that opens at target weight. the top responsive to internal steam pressure. The seal For the invention bags, the top and bottom ends were A thus opens to provide for the escape of excess steam cut diagonally as shown herein in FGS. 1-5. The stand from the top of the bag during the popping operation. employed was glued to the lower surface of each bag In a typical example of the invention, the bag is 28 cm 20 below the susceptor, as shown in FIGS. 4 and 5. long, each face is 13 cm wide, the gussets are 5 cm deep The tests involved three runs in each oven. Each run (10 cm across), and the height of the stand 17 is 1.9 cm. consisted of the control bag with no stand, the invention Such a bag will have a capacity of 2600 cc and will hold bag with stand folded flat, i.e., collapsed, and the inven a charge of 100 grams of popcorn and shortening, and tion bag with stand erected. The ovens were allowed to replaces a standard rectangular 1600 cc bag that was 25 cool off between the second and third runs. able to hold a charge of only 50 grams, the largest that The response was the volume of popped corn as could previously be used with a standard 23 cm turnta measured to the nearest 100 cc., using the same appara ble. tus and technique for every measurement. Refer now to FIGS. 7-9 which illustrate another The results are summarized in the table below: embodiment of the invention. In this case, the popcorn 30 TABLE bag 50 is generally similar to the bag 10 of FIGS. 1-5 AVERAGE POPPED VOLUMES (cc) except that the ends are cut straight. Thus, the bag 50 Invention includes an upper rectangular panel 51 and a lower (Stand folded to Invention panel 52 of the same shape. The panels 51, 52 are con 35 Control Bag collapsed (Stand nected together along the side edges by means of cen Oven Type (no stand) position) erected) trally extending gusset folds 53 and 55. In the lower Metal Cooking Surface 2O6 2100 2600 panel 52 is provided a microwave heating susceptor 52a 600w, small cavity which becomes hot when exposed to microwave en turntable ergy. The bag 50 is provided with longitudinally spaced Metal cooking surface 300 900 2700 600w, larger cavity apart, laterally extending fold lines 54, 56 that enable turntable the bag to be folded into thirds for compact shipment. Ceramic cooking surface 1750 1900 500 The ends of the bag 50 are cut straight across and thus 450w, small cavity have straight ends 58 and 60 at the ends. The ends of the no turntable Ceramic cooking surface 2700 2800 2500 bag 50 are sealed shut all the way across by means of a 45 655w, larger cavity suitable adhesive providing straight seals adjacent to the turntable straight cut ends 58 and 60. To the lower panel 52 of the bag 50 is bonded a stand as a part of the bag 50 which i.e., surface below bag at floor of oven cavity consists of three foldable legs 62 formed from paper It will be seen in the Table that when the bags are board or from a sheet of foldable plastic. Each of the 50 placed on a metal cooking surface, erecting the stand legs 62 has a base portion 64 that is bonded to the lower will provide a substantial improvement in the volume of wall 52 of the bag 50 and an adjacent leg portion 66 popped corn that results. On the other hand, where the which is connected to the base 64 by means of a pre ovens have a ceramic cooking surface, maintaining the formed crease or fold line 65. When the bag 50 is stand in the collapsed position will result in the greatest shipped, the legs 62 are in the collapsed condition of 55 volume of popped corn. Consequently, the invention FIG. 8. However, when the bag 50 is to be used on provides a unique capability of maximizing the volume turntable 7, the leg portions 66 are folded to the erect of popped corn in ovens with either a metal or a ce position shown in FIGS. 7, 8B and 9, and a centrally ramic floor. located foldable tab 68 is also elevated to an erect posi Many variations of the present invention within the tion as shown in FIG. 8B so that a slot 70 engages the scope of the appended claims will be apparent to those leg portion 66 to securely hold the leg portion 66 in its skilled in the art once the principles described herein are erect position. As in the first embodiment, when the legs understood. 62 are collapsed, the bag 50 can be placed in the micro What is claimed is: wave oven in a lower position, but if the legs 62 are 1. An expandable popcorn bag for microwave pop erected, the bag 50 will be elevated in spaced relation 65 ping of popcorn comprising, ship to the bottom wall of the microwave oven to an a bag body formed from flexible microwave transpar elevated position as shown in FIG. 9 so as to substan ent sheet material including superimposed upper tially increase cooking efficiency, particularly by en and lower face panels having parallel left and right 5,302,790 7 8 side edges, longitudinally extending centrally pro tion when the stand is erected and the legs are jecting gussets folded between the upper and lower upright, and face panels, means for securing at least one of said legs in an erect said bag having top and bottom cut ends, top and position. bottom seals aligned adjacent to the cut ends of the 5 2. The popcorn bag of claim 1 wherein said susceptor bag, comprises a sheet of susceptor material located at said said seals bonding the upper and lower face panels lower force panel of said bag to which said stand is together and bonding the gussets between the face attached. panels to seal the ends of the bag whereby said bag 3. The popcorn bag of claim 1 wherein the susceptor expands to accommodate expansion of popcorn as O is attached to the lower face panel and said susceptor the popcorn pops therein during microwave cook comprises a thin film of plastic resinous material having ling, a semiconductive metal-containing coating thereon for said lower face panel having a microwave heating converting microwave energy to heat for enhancing susceptor for absorbing microwave energy to en cooking of the popcorn and said stand is bonded to an hance the popping of said popcorn, 15 outside surface of the lowerface panel proximate to said a collapsible stand as a part of the bag bonded to an susceptor. outside surface of the lower face panel of said bag 4. The popcorn bag of claim 1 wherein the bag has below the susceptor for supporting said bag in top and bottom cut ends and each of the cut ends is spaced relationship above a cooking surface when contoured to provide a convex arcuate cut end at each the stand is erected, 20 end of the bag, arcuate lines of adhesive are aligned said stand is folded to a collapsed condition so that adjacent to the convex arcuate cut ends of the bag, said said stand occupies a reduced space during ship arcuate lines of adhesive bond said face panels together ment and storage, and bond the gussets between the face panels, the gus said stand enables the bag to be placed in selected sets have top and bottom cut ends, the top and bottom positions within said microwave oven during cook 25 cut ends of the gussets are cut so that the length of each ing including a) a lower position when the stand is gusset is greatest near the center of the bag and dimin folded to the collapsed condition and b) a raised ishes proceeding outwardly toward side edges of each position when the stand is folded to an erect condi face panel. tion, 5. The popcorn bag of claim 4 wherein the arcuate said stand being thereby adapted to support the bag in 30 cut ends of the bag and gussets are curved arcs. said selected positions during cooking while the 6. The popcorn bag of claim.4 wherein the arcuate bag remains sealed for improving cooking effi cut ends of the bag are formed from a plurality of - ciency in microwave ovens, straight segments connected end-to-end. said stand comprises base portions adhesively bonded 7. The popcorn bag of claim 1 wherein the stand to an outer surface of said lower panel of the bag, 35 includes a bottom panel connected between the lower at least two upright panels spaced apart from one ends of said legs by spaced apart mutually parallel fold another and connected to said base portions by lines which are also positioned parallel to said fold lines means of fold lines whereby the upright panels between said base portions and said legs. serve as legs for supporting the bag in a raise posi

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